The present invention relates to a flat knitting machine with at least two oppositely located needle beds with stitch formers and/or cam gap plates.
Flat knitting machines as a rule nowadays fixed comb gap widths, which represent a compromise between the desire to provide a maximum possible comb gap width for wear-free formation of the stitches and the desire to provide a minimum comb gap width to maintain the shortest possible thread length from the stitch head of the needle of the front needle bed to the stitch head of the needle of the rear needle bed.
It is however known that in many knitting articles, in particular double-face knitted articles the stitch formation can be optimized when the comb gap width is changed in correspondence with the used yarn thickness. A method has been proposed, in which the comb gap width can be changed by displacing the needle beds parallel to their longitudinal axes. This comb gap width is then maintained until the machine is converted to the production of a different knitted article. Such a method is disclosed for example in the German patent document DE GM 1 827 478. The comb gap width can be adjusted within certain steps. The German patent document DE PS 569 752 discloses a method in which a stepless displacement of the needle beds and thereby a stepless adjustment of the comb gap width is possible. These known methods, in which a displacement of the total needle bed is required are however performed only manually and not during the knitting process.
The European patent document EP OS 0 533 414 discloses a flat knitting machine, in which the knocking over base of the needle bed is formed by plates. These plates can be reciprocatingly displacable over controlled cams located on a cam plate of the carriage, toward the machine longitudinal axis or from it. Thereby no change of the comb gap width is produced, but this method provides with double-face knitting products, a similar effect as the change of the comb gap width.
In the flat knitting machine disclosed in the European patent document EP OS 0 897 027, the stitch former performs a turning movement to the machine longitudinal axis or from it. Here also the movement of the stitch former is performed via a control cap which is located on the lock plate. A rear change of the comb gap width does not take place here, but with this method the quality of the single-face knitted product can be improved, and its at most each second needle of a needle bed forms stitches.
The action of plates or stitch formers via control cams which are arranged on the carriage leads in the known methods to the fact that the knocking over base is located in an exactly defined distance to the machine longitudinal axis only as the plates are in engagement with the control cam. During the remaining time of the carriage movement they however assume different positions which negatively act on the uniformity of the stitch formation. A further disadvantage of the control of the machine formers and plates via control cams of the lock plate is that, the control cams of the lock plates expand in direction toward the machine longitudinal axis and thereby the engagement region to the elements which form the stitches is reduced for the operator of the machine.
Accordingly, it is an object of the present invention to provide a flat knitting machine, which eliminates the disadvantages of the prior art.
More particularly, it is an object of the present invention to provide a flat knitting machine in which for increase of the quality of the stitch formation, in particular the comb gap width, it is adjustable during the knitting process without moving the needle beds.
In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a flat knitting machine with at least two oppositely located needle beds with stitch formers and/or comb gap plates, in which for changing the comb gap width the stitch formers and/or the comb gap plates of at least one needle bed, in which a wire which forms the knocking off base for the machine is fitted are jointly displaceble on the needle bed.
In the inventive flat knitting machine, an adjustment of the comb gap width is possible over the whole length of the needle bed, without moving the needle beds themselves. The adjusted comb gap width remains until a needle adjustment is needed. Therefore the adjustment of the stitch formers and/or comb gap plate is performed during knitting process. The adjustment of the stitch formers and/or comb gap plates can be performed independently from the position of the carriage. Therefore the carriage position and speed must not be changed for adjusting of the comb gap width.
In accordance with a preferable embodiment of the inventive flat knitting machine, the wire which forms the knocking off base for stitches is fixed in each second machine former of a needle bed, and the intermediate stitch formers are arranged so that they are jointly adjustable to the stitch formers which serve for fixing the wires. The stitch formers which do not serve for fixing the knocking off wire can assume a different position than the stitch formers for fixing the knocking off wire and thereby also another position relative to the knocking off base than the others.
When the flat knitting machine is designed with more possibilities to influence the comb gap, the knocking off base for the wire which forms the stitches can be fixed in the comb gap plate, and the comb gap plate can be arranged adjustably in the needle bed together and independently from the jointly adjustable stitch formers. Therefore three types of the stitch formers can be provided, which are arranged independently from one another and adjustably on the needle beds. Thereby the independently adjustable elements are formed: the comb gap plates, and the stitch formers of the first and second types.
Preferably the stitch formers and/or the comb gap plates are arranged adjustably so that, they are guided in each adjustment position so that in different positions of the stitch formers and the comb gap plate are excluded, which is disadvantageous for the uniformity of the stitch forming.
For driving, the stitch formers and/or the comb gap plates can be supported on strips which are displaceable longitudinally and/or transversely to the needle bed longitudinal direction. The strips can be provided with at least two longitudinal openings which are inclined to the needle bed longitudinal axis, and guiding pins which are mounted on needle beds can extend through the longitudinal openings. By supporting the stitch formers and/or comb gap plates on the strips, the displacement of the strips which is guided by the guiding pins can perform a movement of the stitch formers and/or comb gap plates to the machine longitudinal axis and from it. Correspondingly the comb gap increases or reduces.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accombanying drawings.